Đáp án:
$\begin{array}{l}
a){x^2} - {y^2}\\
= \left( {x - y} \right)\left( {x + y} \right)\\
= \left( {87 - 13} \right)\left( {87 + 13} \right)\\
= 74.100\\
= 7400\\
b){x^3} - 3{x^2} + 3x - 1\\
= {\left( {x - 1} \right)^3}\\
= {\left( {101 - 1} \right)^3} = {100^3}\\
= 1000000\\
c){x^3} + 9{x^2} + 27x + 27\\
= {\left( {x + 3} \right)^3}\\
= {\left( {97 + 3} \right)^3}\\
= {100^3}\\
= 1000000\\
d){x^3} + 3{x^2} + 3x\\
= {x^3} + 3{x^2} + 3x + 1 - 1\\
= {\left( {x + 1} \right)^3} - 1\\
= {\left( {99 + 1} \right)^3} - 1\\
= 1000000 - 1\\
= 999999
\end{array}$
